听众在音乐厅听到美妙的歌声是通过 ____传到听众耳朵里的，舞台上一位男高音歌手的“高”音，是指他的声音的 ____（填声音的特性）高．

在一个圆柱形容器内盛有深为20厘米的水，现将一质量为200克的密闭空心铁盒A放入水中时，空心铁盒有一半浮出水面；当铁盒上放一个小磁铁 B 时，铁盒恰好浸没水中，如图甲所示；当把它们倒置在水中时，A有 $\frac{\text{1}}{\text{15}}$ 的体积露出水面，如图乙所示。小磁铁 B 的密度为____千克/米³。

古诗文名句默写。

①自古逢秋悲寂寥，____。              （刘禹锡《秋词》其一）

②____，应傍战场开。          （岑参《行军九日思长安故园》）

③闲云潭影日悠悠，____。                  (王勃《滕王阁诗》)

④____，江月年年只相似。              (张若虚《春江花月夜》)

⑤荷风送香气， ____。            (孟浩然《夏日南亭怀辛大》)

⑥夜阑卧听风吹雨，____。    (陆游《十一月四日风雨大作》其二)

⑦____，鸟鸣山更幽。                      (王籍《入若耶溪》)

⑧____，猛志固常在。           (陶渊明《读山海经十三首》其十)

⑨不知何处吹芦管，____。            (李益《夜上受降城闻笛》)

⑩渡头余落日,____。         （王维《辋川闲居赠裴秀才迪》）

⑪《观沧海》一诗中，以描绘草木来烘托大海美丽多姿的句子是____，____。

⑫《论语》十二章中，多处提及学习方法，如经常复习学过的知识便会有新的发现和体会，并可以凭此成为老师，孔子说____，____。

当前世界上日益严重的环境问题主要来源于（　　）

    Most cities and towns in China have night markets(市场). During the day, these streets are quiet. At night, they become crowded(拥挤的)and lively. Usually, people get there at three or four in the afternoon. By 6:00, the streets are like rivers of people. Night markets are fun places to shop. You can buy clothes, shoes, and many other things. If you think the price is too high, you can bargain with the seller. You can also buy nice food. When you are hungry, you can sit down for a meal. Smelly tofu is popular, but it really smells bad! The best thing is that everything in night markets is cheap!